Addendum to "A generalization of a result on the sum of element orders of a finite group" [arXiv:2001.07275]

Abstract

Let $G$ be a group of order $n$ and $H$ be a subgroup of order $m$ of $G$. Denote by ${\psi }_H(G)$ the sum of element orders relative to $H$ of $G$. It is known that if $G$ is nilpotent, then ${\psi }_H(G)\le {\psi }_{H_m}(G)$, where $H_m$ is the unique subgroup of order $m$ of $C_n$. In this note, we show that this inequality does not hold for infinitely many finite solvable groups.

6 pages